将数据加载到没有空白的组合框 [英] loading data to combo box with out blanks

问题描述

我有一些代码将问题从我的MSSQL服务器加载到组合框中。代码工作，它加载数据，但当我从下拉列表中选择项目时，它会从SQL表中加载所有空白区域。



这是我的代码：

  private   void  loadlocationcombobox（）
 {
  string  constr = ConfigurationManager.ConnectionStrings [  SQLServer]。ConnectionString; 
  string  query =  从dbo中选择location_name .Location; 
 
 SqlConnection con =  new  SqlConnection（constr）; 
 SqlCommand command =  new  SqlCommand（query，con）; 
 con.Open（）; 
 SqlDataReader sqlreader = command.ExecuteReader（）; 
 
 
 
 尝试 
 {
  while （sqlreader.Read（））
 {
 comboLocation.Items.Add（sqlreader [ 0 ]）; 
} 
 
} 
  catch （Exception ex）
 {
 MessageBox.Show（  发生错误： + ex.Message，   error，MessageBoxButtons.OK，MessageBoxIcon.Error）; 
} 
 最后 
 {
 sqlreader.Close（）; 
 con.Close（）; 
} 
} 

任何帮助都会很棒，因为我一直都很棒查看代码，但无法看到如何修复它。

解决方案

尝试将char转换为varchar，如下所示

 选择 CAST（RTRIM（location_name） AS   VARCHAR （ 50 ））来自 dbo.Location 

如果我理解你的问题，你想限制加载空格到组合

 选择 location_name 来自 dbo.Location  where  isnull（location_name，' '）<> ' ' 

Hi,

im have a problem with some code to load data from my MSSQL server in to a combo box. the code works and it loads the data but when i select the item from the drop down it loads all the blank space from the SQL table aswell.

this is my code:

private void loadlocationcombobox()
        {
            string constr = ConfigurationManager.ConnectionStrings  ["SQLServer"].ConnectionString;
            string query = "select location_name from dbo.Location";

            SqlConnection con = new SqlConnection(constr);
            SqlCommand command = new SqlCommand(query, con);
            con.Open();
            SqlDataReader sqlreader = command.ExecuteReader();



            try
            {
                while (sqlreader.Read())
                {
                    comboLocation.Items.Add(sqlreader[0]);
                }

            }
            catch (Exception ex)
            {
                MessageBox.Show("A error has occurred: " + ex.Message, "error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            finally
            {
                sqlreader.Close();
                con.Close();
            }
        }

any help would be great as i have been looking at the code but just cant see how to fix it.

解决方案

try converting char to varchar as follows

select CAST(RTRIM(location_name) AS VARCHAR(50)) from dbo.Location

If I understood your problem correctly, you want to restrict loading blank spaces from to the combo

select location_name from dbo.Location where isnull(location_name ,'')<>''

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