Chapter 6: Visual Studio C Code Placement
Two-Way Communication
These are the procedures used for two-way communication between a main window and a child window, using the code listing that follows :
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Main window
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OR011 and OR012: Declare public, global string variables strGrandmaMoses and strGrandmaJuliette so the data the user enters into the text boxes may be sent to Form2 and Form3 (private won t work).
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OR251 and OR252: Convert any declarations of variables in main that must receive data from the child windows from private to public (label6 and label7).
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OR042: Create child window Form2 and send the main window handle named this to that child window so it can send data back to the main window later.
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OR052: Create child window Form3 and send the main window handle named this to that child window so it can send data back to the main window later.
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Child window (Grandma Moses House)
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OR311: Create a public Form1 variable within Form2 to receive the main window handle: public Form1 frm1Parent.
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OR312: Receive the Form1 handle (named frm1) as an argument in the Form2 class: Form1 frm1.
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OR314: Place the handle name into frm1Parent: frm1Parent = frm1.
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OR322: Transfer the message from the main window to label2 in the child window: label2.Text = frm1Parent.strGrandmaMoses.
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OR332: Transfer the message from the child window to a main window address: frm1Parent.label6.Text = textBox1.Text.
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Child window (Grandma Juliette s House)
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OR481: Create a public Form1 variable in Form3 to receive the main window handle: public Form1 frm1Parent.
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OR482: Receive the Form1 handle (named frm1) as an argument in the Form3 class: Form1 frm1.
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OR484: Place the handle name into frm1Parent: frm1Parent = frm1.
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OR502: Transfer the message from the main window to label2 in the child window: label2.Text = frm1Parent.strGrandma-Juliette.
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OR512: Transfer the message from the child window to a main window address: frm1Parent.label7.Text = textBox1.Text.
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| 1. | Are the two child windows able to talk to one another? |
Answers
| 1. | No, the child windows can only pass information to the main window. It would be possible to construct a means of communication between the two, but the data would always have to be placed in a persistent location in main by one child window and retrieved by the other child window. |
The complete OverTheRiverAndThroughTheWoods code is shown below:
OverTheRiverAndThroughTheWoods (OR) Listing
Form1.cs: OR001: using System; OR002: using System.Collections.Generic; OR003: using System.ComponentModel; OR004: using System.Windows.Forms; OR005: using System.Data; OR006: using System.Drawing; OR007: namespace OverTheRiverAndThroughTheWoods OR008: { OR009: partial class Form1 : Form OR010: { // These are two programmer-added items: OR011: public string strGrandmaMoses; OR012: public string strGrandmaJuliette; OR013: public Form1() OR014: { OR015: InitializeComponent(); OR016: } //-----------------------------------------------------------------------------------------// OR020: private void button1_Click(object sender, EventArgs e) OR021: { // Send Grandma Moses message. // Place this message into a public string, for transport to Form2. OR022: strGrandmaMoses = textBox1.Text; OR023: } //-----------------------------------------------------------------------------------------// OR030: private void button2_Click(object sender, EventArgs e) OR031: { // Send Grandma Juliette message. // Place this message into a public string, for transport to Form3. OR032: strGrandmaJuliette = textBox2.Text; OR033: } //-----------------------------------------------------------------------------------------// OR040: private void button3_Click(object sender, EventArgs e) OR041: { // Going to Grandma Moses' house. // Create Form2 (Grandma Moses' house). // 'this' in the next line refers to the main window's 'handle'. OR042: Form2 frm2 = new Form2(this); OR043: frm2.ShowDialog(); OR044: frm2.Close(); OR045: } //-----------------------------------------------------------------------------------------// OR050: private void button4_Click(object sender, EventArgs e) OR051: { // Going to Grandma Juliette's house. // Create Form3 (Grandma Juliette's house). // 'this' in the next line refers to the main window's 'handle'. OR052: Form3 frm3 = new Form3(this); OR053: frm3.ShowDialog(); OR054: frm3.Close(); OR055: } //-----------------------------------------------------------------------------------------// OR060: private void button5_Click(object sender, EventArgs e) OR061: { // Quit this project. OR062: Close(); OR063: } OR064: } OR065: } //=========================================================================================// Form1.Designer.cs: OR080: namespace OverTheRiverAndThroughTheWoods OR081: { OR082: partial class Form1 OR083: { // Required designer variable. OR084: private System.ComponentModel.IContainer components = null; // Clean up any resources being used. OR085: protected override void Dispose(bool disposing) OR086: { OR087: if (disposing && (components != null)) OR088: { OR089: components.Dispose(); OR090: } OR091: base.Dispose(disposing); OR092: } OR093: #region Windows Form Designer generated code // Required method for Designer support - do not modify OR094: private void InitializeComponent() OR095: { OR096: this.label1 = new System.Windows.Forms.Label(); OR097: this.label2 = new System.Windows.Forms.Label(); OR098: this.label3 = new System.Windows.Forms.Label(); OR099: this.textBox1 = new System.Windows.Forms.TextBox(); OR100: this.textBox2 = new System.Windows.Forms.TextBox(); OR101: this.groupBox1 = new System.Windows.Forms.GroupBox(); OR102: this.label7 = new System.Windows.Forms.Label(); OR103: this.label6 = new System.Windows.Forms.Label(); OR104: this.label5 = new System.Windows.Forms.Label(); OR105: this.label4 = new System.Windows.Forms.Label(); OR106: this.button1 = new System.Windows.Forms.Button(); OR107: this.button2 = new System.Windows.Forms.Button(); OR108: this.button3 = new System.Windows.Forms.Button(); OR109: this.button4 = new System.Windows.Forms.Button(); OR110: this.button5 = new System.Windows.Forms.Button(); OR111: this.groupBox1.SuspendLayout(); OR112: this.SuspendLayout(); // // label1 // OR113: this.label1.AutoSize = true; OR114: this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 14F, System.Drawing.FontStyle.Underline, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR115: this.label1.Location = new System.Drawing.Point(100, 8); OR116: this.label1.Name = "label1"; OR117: this.label1.Size = new System.Drawing.Size(341, 24); OR118: this.label1.TabIndex = 0; OR119: this.label1.Text = "Over the River and Through the Woods"; // // label2 // OR120: this.label2.AutoSize = true; OR121: this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR122: this.label2.Location = new System.Drawing.Point(24, 52); OR123: this.label2.Name = "label2"; OR124: this.label2.Size = new System.Drawing.Size(206, 17); OR125: this.label2.TabIndex = 1; OR126: this.label2.Text = "Send Note to Grandma Moses ->"; // // label3 // OR127: this.label3.AutoSize = true; OR128: this.label3.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, (byte)(0))); OR129: this.label3.Location = new System.Drawing.Point(24, 86); OR130: this.label3.Name = "label3"; OR131: this.label3.Size = new System.Drawing.Size(209, 17); OR132: this.label3.TabIndex = 2; OR133: this.label3.Text = "Send Note to Grandma Juliette ->"; // // textBox1 // OR134: this.textBox1.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR135: this.textBox1.Location = new System.Drawing.Point(235, 50); OR136: this.textBox1.Name = "textBox1"; OR137: this.textBox1.Size = new System.Drawing.Size(200, 23); OR138: this.textBox1.TabIndex = 3; // // textBox2 // OR139: this.textBox2.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR140: this.textBox2.Location = new System.Drawing.Point(235, 84); OR141: this.textBox2.Name = "textBox2"; OR142: this.textBox2.Size =new System.Drawing.Size(200,23); this.textBox2.TabIndex = 4; // // groupBox1 // OR143: this.groupBox1.Controls.Add(this.label7); OR144: this.groupBox1.Controls.Add(this.label6); OR145: this.groupBox1.Controls.Add(this.label5); OR146: this.groupBox1.Controls.Add(this.label4); OR147: this.groupBox1.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Underline, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR148: this.groupBox1.Location = new System.Drawing.Point(28, 120); OR149: this.groupBox1.Name = "groupBox1"; OR150: this.groupBox1.Size = new System.Drawing.Size(488, 64); OR151: this.groupBox1.TabIndex = 5; OR152: this.groupBox1.TabStop = false; OR153: this.groupBox1.Text = "Messages From Our Grandmothers"; OR154: this.groupBox1.Enter += new System.EventHandler(this.groupBox1_Enter); // // label7 // OR155: this.label7.AutoSize = true; OR156: this.label7.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR157: this.label7.Location = new System.Drawing.Point(75, 40); OR158: this.label7.Name = "label7"; OR159: this.label7.Size = new System.Drawing.Size(0, 0); OR160: this.label7.TabIndex = 3; // // label6 // OR161: this.label6.AutoSize = true; OR162: this.label6.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR163: this.label6.Location = new System.Drawing.Point(75, 20); OR164: this.label6.Name = "label6"; OR165: this.label6.Size = new System.Drawing.Size(0, 0); OR166: this.label6.TabIndex = 2; // // label5 // OR167: this.label5.AutoSize = true; OR168: this.label5.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR169: this.label5.Location = new System.Drawing.Point(16, 40); OR170: this.label5.Name = "label5"; OR171: this.label5.Size = new System.Drawing.Size(52, 17); OR172: this.label5.TabIndex = 1; OR173: this.label5.Text = "Juliette:"; // // label4 // OR174: this.label4.AutoSize = true; OR175: this.label4.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR176: this.label4.Location = new System.Drawing.Point(16, 20); OR177: this.label4.Name = "label4"; OR178: this.label4.Size = new System.Drawing.Size(49, 17); OR179: this.label4.TabIndex = 0; OR180: this.label4.Text = "Moses:"; // // button1 // OR181: this.button1.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR182: this.button1.Location = new System.Drawing.Point(452, 50); OR183: this.button1.Name = "button1"; OR184: this.button1.Size = new System.Drawing.Size(60, 22); OR185: this.button1.TabIndex = 6; OR186: this.button1.Text = "Send"; OR187: this.button1.Click += new System.EventHandler(this.button1_Click); // // button2 // OR188: this.button2.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR189: this.button2.Location = new System.Drawing.Point(452, 84); OR190: this.button2.Name = "button2"; OR191: this.button2.Size = new System.Drawing.Size(60, 22); OR192: this.button2.TabIndex = 7; OR193: this.button2.Text = "Send"; OR194: this.button2.Click += new System.EventHandler(this.button2_Click); // // button3 // OR195: this.button3.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR196: this.button3.Location = new System.Drawing.Point(50, 195); OR197: this.button3.Name = "button3"; OR198: this.button3.Size = new System.Drawing.Size(200, 23); OR199: this.button3.TabIndex = 8; OR200: this.button3.Text = "Going to Grandma Moses\' House"; OR201: this.button3.Click += new System.EventHandler(this.button3_Click); // // button4 // OR202: this.button4.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR203: this.button4.Location = new System.Drawing.Point(300, 195); OR204: this.button4.Name = "button4"; OR205: this.button4.Size = new System.Drawing.Size(200, 23); OR206: this.button4.TabIndex = 9; OR207: this.button4.Text = "Going to Grandma Juliette\'s House"; OR208: this.button4.Click += new System.EventHandler(this.button4_Click); // // button5 // OR209: this.button5.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR210: this.button5.Location = new System.Drawing.Point(208, 226); OR211: this.button5.Name = "button5"; OR212: this.button5.Size = new System.Drawing.Size(125, 23); OR213: this.button5.TabIndex = 10; OR214: this.button5.Text = "Quit this Project"; OR215: this.button5.Click += new System.EventHandler(this.button5_Click); // // Form1 // OR216: this.AutoScaleDimensions = new System.Drawing.SizeF(5F, 13F); OR217: this.ClientSize = new System.Drawing.Size(542, 266); OR218: this.Controls.Add(this.button5); OR219: this.Controls.Add(this.button4); OR220: this.Controls.Add(this.button3); OR221: this.Controls.Add(this.button2); OR222: this.Controls.Add(this.button1); OR223: this.Controls.Add(this.groupBox1); OR224: this.Controls.Add(this.textBox2); OR225: this.Controls.Add(this.textBox1); OR226: this.Controls.Add(this.label3); OR227: this.Controls.Add(this.label2); OR228: this.Controls.Add(this.label1); OR229: this.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Underline, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR230: this.Name = "Form1"; OR231: this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen; OR232: this.Text = "Over The River and Through The Woods"; OR233: this.groupBox1.ResumeLayout(false); OR234: this.groupBox1.PerformLayout(); OR235: this.ResumeLayout(false); OR236: this.PerformLayout(); OR237: } OR238: #endregion OR239: private System.Windows.Forms.Label label1; OR240: private System.Windows.Forms.Label label2; OR241: private System.Windows.Forms.Label label3; OR242: private System.Windows.Forms.TextBox textBox1; OR243: private System.Windows.Forms.TextBox textBox2; OR244: private System.Windows.Forms.GroupBox groupBox1; OR245: private System.Windows.Forms.Label label4; OR246: private System.Windows.Forms.Button button1; OR247: private System.Windows.Forms.Button button2; OR248: private System.Windows.Forms.Button button3; OR249: private System.Windows.Forms.Button button4; OR250: private System.Windows.Forms.Button button5; // These next two labels must be converted from private to public: OR251: public System.Windows.Forms.Label label6; OR252: public System.Windows.Forms.Label label7; OR253: private System.Windows.Forms.Label label5; OR254: } OR255: } //=========================================================================================// Form2.cs: OR300: using System; OR301: using System.Collections.Generic; OR302: using System.ComponentModel; OR303: using System.Data; OR304: using System.Drawing; OR305: using System.Text; OR306: using System.Windows.Forms; OR307: namespace OverTheRiverAndThroughTheWoods OR308: { OR309: partial class Form2 : Form OR310: { // This is a programmer-added item: OR311: public Form1 frm1Parent; // OR312: public Form2(Form1 frm1) OR313: { OR314: frm1Parent = frm1; OR315: InitializeComponent(); OR316: } //-----------------------------------------------------------------------------------------// OR320: private void Form2_Load(object sender, EventArgs e) OR321: { // Place the main window's message into 'label2'. OR322: label2.Text = frm1Parent.strGrandmaMoses; OR323: } //----------------------------------------------------------------------------------------// OR330: private void button1_Click(object sender, EventArgs e) OR331: { // Place the return message into persistent storage in Form1: OR332: frm1Parent.label6.Text = textBox1.Text; OR333: Close(); OR334: } OR335: } OR336: } //========================================================================================// Form2.Designer.cs: OR360: namespace OverTheRiverAndThroughTheWoods OR361: { OR362: partial class Form2 OR363: { // Required designer variable. OR364: private System.ComponentModel.IContainer components = null; // Clean up any resources being used. OR365: protected override void Dispose(bool disposing) OR366: { OR367: if (disposing && (components != null)) OR368: { OR369: components.Dispose(); OR370: } OR371: base.Dispose(disposing); OR372: } OR373: #region Windows Form Designer generated code // Required method for Designer support - do not modify OR374: private void InitializeComponent() OR375: { OR376: this.label1 = new System.Windows.Forms.Label(); OR377: this.label2 = new System.Windows.Forms.Label(); OR378: this.label3 = new System.Windows.Forms.Label(); OR379: this.textBox1 = new System.Windows.Forms.TextBox(); OR380: this.button1 = new System.Windows.Forms.Button(); OR381: this.SuspendLayout(); // // label1 // OR382: this.label1.AutoSize = true; OR383: this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Underline, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR384: this.label1.Location = new System.Drawing.Point(16, 16); OR385: this.label1.Name = "label1"; OR386: this.label1.Size = new System.Drawing.Size(140, 17); OR387: this.label1.TabIndex = 0; OR388: this.label1.Text = "Message From Home:"; // // label2 // OR389: this.label2.AutoSize = true; OR390: this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR391: this.label2.Location = new System.Drawing.Point(16, 40); OR392: this.label2.Name = "label2"; OR393: this.label2.Size = new System.Drawing.Size(0, 0); OR394: this.label2.TabIndex = 1; // // label3 // OR395: this.label3.AutoSize = true; OR396: this.label3.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Underline, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR397: this.label3.Location = new System.Drawing.Point(16, 72); OR398: this.label3.Name = "label3"; OR399: this.label3.Size = new System.Drawing.Size(156, 17); OR400: this.label3.TabIndex = 2; OR401: this.label3.Text = "Send Message to Home:"; // // textBox1 // OR402: this.textBox1.Font = new System.Drawing.Font("Microsoft Sans Serif", 10F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0))); OR403: this.textBox1.Location = new System.Drawing.Point(24, 94); OR404: this.textBox1.Name = "textBox1"; OR405: this.textBox1.Size = new System.Drawing.Size(340, 23); OR406: this.textBox1.TabIndex = 3; // // button1 // OR407: this.button1.Location = new System.Drawing.Point(137, 128); OR408: this.button1.Name = "button1"; OR409: this.button1.Size = new System.Drawing.Size(125, 23); OR410: this.button1.TabIndex = 4; OR411: this.button1.Text = "Return to Home"; OR412: this.button1.Click += new System.EventHandler(this.button1_Click); // // Form2 // OR413: this.AutoScaleDimensions = new System.Drawing.SizeF(5F, 13F); OR414: this.ClientSize = new System.Drawing.Size(392, 166); OR415: this.Controls.Add(this.button1); OR416: this.Controls.Add(this.textBox1); OR417: this.Controls.Add(this.label3); OR418: this.Controls.Add(this.label2); OR419: this.Controls.Add(this.label1); OR420: this.Name = "Form2"; OR421: this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen; OR422: this.Text = "Grandma Moses\' House"; OR423: this.Load += new System.EventHandler(this.Form2_Load); OR424: this.ResumeLayout(false); OR425: this.PerformLayout(); OR426: } OR427: #endregion OR428: private System.Windows.Forms.Label label1; OR429: private System.Windows.Forms.Label label2; OR430: private System.Windows.Forms.Label label3; OR431: private System.Windows.Forms.TextBox textBox1; OR432: private System.Windows.Forms.Button button1; OR433: } OR434: } //=========================================================================================// Form3.cs: OR470: using System; OR471: using System.Collections.Generic; OR472: using System.ComponentModel; OR473: using System.Data; OR474: using System.Drawing; OR475: using System.Text; OR476: using System.Windows.Forms; OR477: namespace OverTheRiverAndThroughTheWoods OR478: { OR479: partial class Form3 : Form OR480: { // This is a programmer-added item: OR481: public Form1 frm1Parent; // OR482: public Form3(Form1 frm1) OR483: { OR484: frm1Parent = frm1; OR485: InitializeComponent(); OR486: } //-----------------------------------------------------------------------------------------// OR500: private void Form3_Load(object sender, EventArgs e) OR501: { // Place the main window's message into 'label2'. OR502: label2.Text = frm1Parent.strGrandmaJuliette; OR503: } //-----------------------------------------------------------------------------------------// OR510: private void button1_Click(object sender, EventArgs e) OR511: { // Place the return message into persistent storage in Form1: OR512: frm1Parent.label7.Text = textBox1.Text; OR513: Close(); OR514: } OR515: } OR516: } //=========================================================================================// Form3.Designer.cs [This is a repeat of Form2 Designer, replacing Grandma Moses with Grandma Juliette. //=========================================================================================// 
Unlocking Microsoft C# V 2.0 Programming Secrets (Wordware Applications Library)
ISBN: 1556220979
EAN: 2147483647
EAN: 2147483647
Year: 2005
Pages: 129
Pages: 129
Authors: Richard Braden
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