如何使用ComboBox中的选定值进行SQL查询?

问题描述

当我在ComboBox中选择一个值时.如何使用它们查询SQL?

When I choose a value in ComboBox. How can I use them to query SQL??

我尝试过

private void cmb1_SelectedIndexChanged(object sender, EventArgs e)
{
   string select = this.cmb1.GetItemText(this.cmb1.SelectedItem);
   cm1 = new SqlCommand("select VS from DATABASE where ROUND=select", con);
   ap = new SqlDataAdapter(cm1);
   ds = new System.Data.DataSet();
   ap.Fill(ds, "DATABASE");
   cmb2.DataSource = ds.Tables[0]; 
   cmb2.DisplayMember = "VS"; // show in combobox2
}

我想使用变量 select 进行查询，但是它不起作用.

I want to use the variable select to query but it doesn't work.

推荐答案

您需要将 select 传递给sql参数

You need to pass your select to sql parameter

string select = this.cmb1.GetItemText(this.cmb1.SelectedItem);
cm1 = new SqlCommand("select VS from DATABASE where ROUND=@round", con);
cm1.Parameters.Add("@round", SqlDbType.NVarChar, -1);
cm1.Parameters["@round"].Value = select ;

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