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i have a textbox and a list box. In textchanges event of textbox i m filling listbox from database
and then select value from listbox and calling another value and then saving data.. i want that if user doesn't select any value from listbox and leaving textbox by typing false value which listbox doesn't contains i want to stop him...


the code i tried is

btnclick

C#
if(listbox1.items.contains(textbox1))
{
   //calling another value. from database 
} 

else
messagebox.show("Please select a value from searchbox");



Thanks in advance....
Posted
Updated 7-May-13 20:50pm
v2
Comments
KM Perumal 8-May-13 2:21am    
Try this
if(listbox1.items.contains(textbox1.text))

C#
// CODE FOR designer FILE
namespace WindowsApplication1
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        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.txt = new System.Windows.Forms.TextBox();
            this.lst = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            // 
            // txt
            // 
            this.txt.Location = new System.Drawing.Point(40, 21);
            this.txt.Name = "txt";
            this.txt.Size = new System.Drawing.Size(325, 20);
            this.txt.TabIndex = 0;
            this.txt.TextChanged += new System.EventHandler(this.txt_TextChanged);
            this.txt.KeyDown += new System.Windows.Forms.KeyEventHandler(this.txt_KeyDown);
            this.txt.Leave += new System.EventHandler(this.txt_Leave);
            this.txt.Enter += new System.EventHandler(this.txt_Enter);
            // 
            // lst
            // 
            this.lst.FormattingEnabled = true;
            this.lst.Location = new System.Drawing.Point(12, 37);
            this.lst.Name = "lst";
            this.lst.Size = new System.Drawing.Size(10, 4);
            this.lst.TabIndex = 1;
            this.lst.Visible = false;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(406, 309);
            this.Controls.Add(this.lst);
            this.Controls.Add(this.txt);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox txt;
        private System.Windows.Forms.ListBox lst;
    }
}


C#
// CODE FOR cs FILE
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        DataTable tblList = new DataTable();
        DataView dvList = null;

        public Form1()
        {
            InitializeComponent();
        }

        private void txt_TextChanged(object sender, EventArgs e)
        {
            dvList.RowFilter = "Item Like '" + txt.Text + "%'";
        }

        private void txt_Enter(object sender, EventArgs e)
        {
            lst.Width = txt.Width;
            lst.Height = 100;

            lst.Top = txt.Top + txt.Height;
            lst.Left = txt.Left;

            if (!lst.Visible)
                lst.Visible = true;
        }

        private void txt_Leave(object sender, EventArgs e)
        {
            if (lst.SelectedIndex != -1)
            {
                txt.Text = lst.Text;
            }
            else
            {
                txt.Text = "";
                MessageBox.Show("Please select from list only !");
            }

            lst.Visible = false;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            tblList.Columns.Add("Item");

            tblList.Rows.Add("ONE");
            tblList.Rows.Add("TWO");
            tblList.Rows.Add("THREE");
            tblList.Rows.Add("FOUR");
            tblList.Rows.Add("FIVE");
            tblList.Rows.Add("SIX");
            tblList.Rows.Add("SEVEN");
            tblList.Rows.Add("EIGHT");
            tblList.Rows.Add("NINE");
            tblList.Rows.Add("TEN");

            lst.DisplayMember = "Item";

            lst.DataSource = tblList;

            dvList = tblList.DefaultView;
        }

        private void txt_KeyDown(object sender, KeyEventArgs e)
        {
            try
            {
                if (e.KeyValue == 38) // UP KEY
                {
                    lst.SelectedIndex = lst.SelectedIndex - 1;
                }
                else if (e.KeyValue == 40) // DOWN KEY
                {
                    lst.SelectedIndex = lst.SelectedIndex + 1;
                }
            }
            catch { }
        }
    }
}
 
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C#
// CODE FOR designer FILE
namespace WindowsApplication1
{
    partial class Form1
    {
        private System.ComponentModel.IContainer components = null;

        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        private void InitializeComponent()
        {
            this.txt = new System.Windows.Forms.TextBox();
            this.lst = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            // 
            // txt
            // 
            this.txt.Location = new System.Drawing.Point(40, 21);
            this.txt.Name = "txt";
            this.txt.Size = new System.Drawing.Size(325, 20);
            this.txt.TabIndex = 0;
            this.txt.TextChanged += new System.EventHandler(this.txt_TextChanged);
            this.txt.KeyDown += new System.Windows.Forms.KeyEventHandler(this.txt_KeyDown);
            this.txt.Leave += new System.EventHandler(this.txt_Leave);
            this.txt.Enter += new System.EventHandler(this.txt_Enter);
            // 
            // lst
            // 
            this.lst.FormattingEnabled = true;
            this.lst.Location = new System.Drawing.Point(12, 37);
            this.lst.Name = "lst";
            this.lst.Size = new System.Drawing.Size(10, 4);
            this.lst.TabIndex = 1;
            this.lst.Visible = false;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(406, 309);
            this.Controls.Add(this.lst);
            this.Controls.Add(this.txt);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox txt;
        private System.Windows.Forms.ListBox lst;
    }
}
//-----------------------------------------------------------------------------------------------
// CODE FOR cs FILE
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        DataTable tblList = new DataTable();
        DataView dvList = null;

        public Form1()
        {
            InitializeComponent();
        }

        private void txt_TextChanged(object sender, EventArgs e)
        {
            dvList.RowFilter = "Item Like '" + txt.Text + "%'";
        }

        private void txt_Enter(object sender, EventArgs e)
        {
            lst.Width = txt.Width;
            lst.Height = 100;

            lst.Top = txt.Top + txt.Height;
            lst.Left = txt.Left;

            if (!lst.Visible)
                lst.Visible = true;
        }

        private void txt_Leave(object sender, EventArgs e)
        {
            if (lst.SelectedIndex != -1)
            {
                txt.Text = lst.Text;
            }
            else
            {
                txt.Text = "";
                MessageBox.Show("Please select from list only !");
            }

            lst.Visible = false;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            tblList.Columns.Add("Item");

            tblList.Rows.Add("ONE");
            tblList.Rows.Add("TWO");
            tblList.Rows.Add("THREE");
            tblList.Rows.Add("FOUR");
            tblList.Rows.Add("FIVE");
            tblList.Rows.Add("SIX");
            tblList.Rows.Add("SEVEN");
            tblList.Rows.Add("EIGHT");
            tblList.Rows.Add("NINE");
            tblList.Rows.Add("TEN");

            lst.DisplayMember = "Item";

            lst.DataSource = tblList;

            dvList = tblList.DefaultView;
        }

        private void txt_KeyDown(object sender, KeyEventArgs e)
        {
            try
            {
                if (e.KeyValue == 38) // UP KEY
                {
                    lst.SelectedIndex = lst.SelectedIndex - 1;
                }
                else if (e.KeyValue == 40) // DOWN KEY
                {
                    lst.SelectedIndex = lst.SelectedIndex + 1;
                }
            }
            catch { }
        }
    }
}
//-----------------------------------------------------------------------------------------------
 
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