Pure C# InputBox

Xcelled194 2 1K Views

One of the things that always irked me about C# is its lack of an InputBox function. In VB, You can simply do

response = InputBox("Enter your name")

Unfortunately, there is no C# equivalent. Sure, you can call the VB one, but doesn't that kind of defeat the purpose of C#? So, like any good programmer, I set out to make my own pure C# InputBox. Its fairly bare bones, but it gives all the functionality of the VB InputBox.

You can use it by including the InputBox class in your program's namespace and calling it like this:

string lang = InputBox.Show("What's your favorite language?", "Language", "C#", -1, -1);

Notes:

  • Because C# 3.5 and below doesn't support optional parameters, you must supply an argument for every parameter.
  • For the xPos and yPos, passing in -1 will center the form in the corresponding direction. (x is horizontal, y is vertical)
  • There is almost nothing in the way of error trapping, because I feel that you, the end programmer, can best trap the errors as suited to your project. Simply surrounding InputBox.Show() with a try statement should prove adequate.
  • If the user presses cancel, InputBox.Show() returns an empty string ("")
  • If you modify/distribute the source code, please retain my information comment, however you may add yourself as an author.
  • PM me with any features you think this should have or any bugs you find.
ddanbe commented: Good. +14 
public sealed class InputBox
    {
    /* Class mimics VB's InputBox function
     * Author: Scott Ketelaar
     * Developed: 4/27/2011
     */
        private class InputBoxForm :Form
        {
            private System.ComponentModel.IContainer components = null;

            /// <summary>
            /// Clean up any resources being used.
            /// </summary>
            /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
            protected override void Dispose(bool disposing)
            {
                if (disposing && (components != null))
                {
                    components.Dispose();
                }
                base.Dispose(disposing);
            }

            #region Windows Form Designer generated code

            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {
                this.cancelBtn = new System.Windows.Forms.Button();
                this.OKbtn = new System.Windows.Forms.Button();
                this.responseBox = new System.Windows.Forms.TextBox();
                this.promptLbl = new System.Windows.Forms.Label();
                this.SuspendLayout();
                // 
                // cancelBtn
                // 
                this.cancelBtn.DialogResult = System.Windows.Forms.DialogResult.Cancel;
                this.cancelBtn.Location = new System.Drawing.Point(291, 117);
                this.cancelBtn.Name = "cancelBtn";
                this.cancelBtn.Size = new System.Drawing.Size(75, 23);
                this.cancelBtn.TabIndex = 1;
                this.cancelBtn.Text = "Cancel";
                this.cancelBtn.UseVisualStyleBackColor = true;
                this.cancelBtn.Click += new System.EventHandler(this.button2_Click);
                // 
                // OKbtn
                // 
                this.OKbtn.Location = new System.Drawing.Point(210, 117);
                this.OKbtn.Name = "OKbtn";
                this.OKbtn.Size = new System.Drawing.Size(75, 23);
                this.OKbtn.TabIndex = 2;
                this.OKbtn.Text = "OK";
                this.OKbtn.UseVisualStyleBackColor = true;
                this.OKbtn.Click += new System.EventHandler(this.button1_Click);
                // 
                // responseBox
                // 
                this.responseBox.Location = new System.Drawing.Point(16, 91);
                this.responseBox.Name = "responseBox";
                this.responseBox.Size = new System.Drawing.Size(350, 20);
                this.responseBox.TabIndex = 4;
                // 
                // promptLbl
                // 
                this.promptLbl.Location = new System.Drawing.Point(13, 13);
                this.promptLbl.Name = "promptLbl";
                this.promptLbl.Size = new System.Drawing.Size(349, 75);
                this.promptLbl.TabIndex = 3;
                this.promptLbl.Text = "promptLbl";
                // 
                // Form1
                // 
                this.AcceptButton = this.OKbtn;
                this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
                this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
                this.CancelButton = this.cancelBtn;
                this.ClientSize = new System.Drawing.Size(374, 152);
                this.Controls.Add(this.responseBox);
                this.Controls.Add(this.promptLbl);
                this.Controls.Add(this.OKbtn);
                this.Controls.Add(this.cancelBtn);
                this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
                this.MaximizeBox = false;
                this.MinimizeBox = false;
                this.Name = "Form1";
                this.ShowIcon = false;
                this.ShowInTaskbar = false;
                this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
                this.ResumeLayout(false);
                this.PerformLayout();
            }

            #endregion

            private System.Windows.Forms.Button cancelBtn;
            private System.Windows.Forms.Button OKbtn;
            private System.Windows.Forms.TextBox responseBox;
            private System.Windows.Forms.Label promptLbl;

            public InputBoxForm()
            {
                InitializeComponent();
            }
            public string Response { get { return this.responseBox.Text; } }
            private void button1_Click(object sender, EventArgs e)
            {
                this.DialogResult = DialogResult.OK;
                this.Close();
            }

            private void button2_Click(object sender, EventArgs e)
            {
                this.DialogResult = DialogResult.Cancel;
                this.responseBox.Text = "";
                this.Close();
            }
            public DialogResult ShowDialog(string Prompt, string Title, string DefaultResponse, int xPos, int yPos)
            {
                try
                {
                    this.promptLbl.Text = Prompt;
                    this.Text = Title;
                    this.responseBox.Text = DefaultResponse;
                    this.CenterToScreen();
                    this.Location = new System.Drawing.Point(
                        (xPos == -1 ? this.Location.X : xPos),
                        (yPos == -1 ? this.Location.Y : yPos));
                    return this.ShowDialog();
                }
                catch (Exception ex)
                {  
                    throw ex;
                }
            }
        }
        /// <summary>
        /// Displays a prompt in a dialog box, waits for the user to input text or click a button, and then returns a string containing the contents of the text box.
        /// </summary>
        /// <param name="Prompt">String expression displayed as the message in the dialog box. The maximum length of Prompt is approximately 1024 characters, depending on the width of the characters used. If Prompt consists of more than one line, you can separate the lines using a carriage return character (\r), a linefeed character (\n), or a carriage return–linefeed character combination (\r\n) between each line.</param>
        /// <param name="Title">String expression displayed in the title bar of the dialog box.</param>
        /// <param name="DefaultResponse">String expression displayed in the text box as the default response if no other input is provided.</param>
        /// <param name="xPos">Numeric expression that specifies the left edge of the dialog box. If xPos is -1, the dialog box is centered horizontally.</param>
        /// <param name="yPos">Numeric expression that specifies the top edge of the dialog box. If yPos is -1, the dialog box is centered vertically.</param>
        /// <returns>A string containing the user's response.</returns>
        public static string Show(string Prompt, string Title, string DefaultResponse, int xPos, int yPos)
        {
            using (InputBoxForm ipb = new InputBoxForm()) {
                ipb.ShowDialog(Prompt, Title, DefaultResponse, xPos, yPos);
                return ipb.Response;
            }
        }
    }
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