如何将组合框的第一个值设置为“选择选项" [英] How to set first value of combo box to 'Select Option'

问题描述

我正在使用以下代码填充组合框，但我想在组合框的第一个索引处输入选择选项"值.

I am using the following code to populate a combobox, but i want ''Select Option'' Value at first index of combobox.

string strConn = "Data Source=SEZSW08;Initial Catalog=Nidhi;Integrated Security=True";
        SqlConnection Con = new SqlConnection(strConn);
        Con.Open();
        string strCmd = "select companyName from companyinfo where CompanyName='" + cmbCompName.SelectedValue + "';";
        SqlCommand Cmd = new SqlCommand(strCmd, Con);
        SqlDataAdapter da = new SqlDataAdapter(strCmd, Con);
        DataSet ds = new DataSet();
        Con.Close();
        da.Fill(ds);
        cmbCompName.DataSource = ds;
        cmbCompName.DisplayMember = "CompanyName";
        cmbCompName.ValueMember = "CompanyName";
        //cmbCompName.DataBind();
        cmbCompName.Enabled = true;

感谢您的帮助.
Usama

I shall be thankful for your help.
Usama

推荐答案

尝试一下:

Try this:

if(cmbCompName.Items.Count > 0)
{
  //You can set using SelectedIndex
  cmbCompName.SelectedIndex= 0;
}

使用..

Use..

cmbCompName.Insert(0,"Select Option");

或，

Or,

cmbCompName.Items.Insert(0, new ListItem("-Select Option-", "0"));

或，
在表单加载事件中，写类似..

Or,
In form load event write something like..

cmbCompName.Text = "Select Option";

然后在comboBox的 TextChanged 事件中编写以下代码..

And in the TextChanged event of the comboBox write the following code..

private void cmbCompName_TextChanged(object sender, EventArgs e)
       {
           if (cmbCompName.SelectedIndex < 0)
           {
               cmbCompName.Text = "Select Option";
           }
           else
           {
               cmbCompName.Text = cmbCompName.SelectedText;
           }
       }

您只需要下面突出显示的三行.大功告成:omg:

You needed just the below high lighted three lines. You are done. :omg:

string strConn = "Data Source=SEZSW08;Initial Catalog=Nidhi;Integrated Security=True";
        SqlConnection Con = new SqlConnection(strConn);
        Con.Open();
        string strCmd = "select companyName from companyinfo where CompanyName='" + cmbCompName.SelectedValue + "';";
        SqlCommand Cmd = new SqlCommand(strCmd, Con);
        SqlDataAdapter da = new SqlDataAdapter(strCmd, Con);
        DataTable ds = new DataTable();
        Con.Close();
        da.Fill(ds);
        DataRow dr = ds.NewRow();//Created new row 
        dr("companyName ") = "Select option";//Added required text
        ds.Rows.InsertAt(dr, 0);//Added at first position
        cmbCompName.DataSource = ds;       
        cmbCompName.DataBind();

此致..:大笑:

Regards..:laugh:

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