参数没有默认值

问题描述

下面有一段代码，这段代码更新了gridview中的下拉列表。数据库在MS Access
中出现错误：参数@RateCenterName没有默认值。

RateCenterID是主键

 字符串updateSql =UPDATE [RateCenters]+SET [RateCenterName] = @RateCenterName，[Province] = @省，[QuantityThreshold] = @ QuantityThreshold+WHERE [RateCenterID] = @ RateCenterID; 
 
字符串ratecenterID; 
 
 protected void GridView1_RowUpdating（object sender，GridViewUpdateEventArgs e）
 {
 GridViewRow row =（GridViewRow）GridView1.Rows [e.RowIndex]; 
 DropDownList ddl =（DropDownList）row.FindControl（DropDownList2）; 
 TextBox rateCenterName =（TextBox）row.FindControl（TextBox1）; 
 TextBox quantityThreshold =（TextBox）row.FindControl（TextBox2）; 
 
 OleDbConnection conn = new OleDbConnection（ConfigurationManager.ConnectionStrings [DBConnection]。ToString（））; 
 OleDbCommand cmd = null; 
 
尝试
 {
 conn.Open（）; 
 cmd = new OleDbCommand（updateSql，conn）; 
 cmd.Parameters.Add（@ RateCenterName，OleDbType.VarChar）.Value = rateCenterName.Text; 
 cmd.Parameters.Add（@ Province，OleDbType.VarChar）.Value = ddl.SelectedValue; 
 cmd.Parameters.Add（@ QuantityThreshold，OleDbType.VarChar）.Value = quantityThreshold.Text; 
 
 cmd.Connection = conn; 
 cmd.ExecuteNonQuery（）; 
 
 GridView1.EditIndex = -1; 
 GridView1.DataBind（）; 
} 
 catch（OleDbException ex）
 {
 throw（ex）; 
} 
 finally 
 {
 cmd.Dispose（）; 
 conn.Close（）; 
 conn.Dispose（）; 
} 
} 
  

请帮我解决这个问题。

问候，

Arjun

解决方案您的查询需要四个参数（ @RateCenterName ， @Province ， @ QuantityThreshold 和 @RateCenterID ），但您只能传递三次。 code> @RateCenterID 缺失。

I have a code below, this code updates the dropdownlist in the gridview. The database is in MS AccessI get the error: "Parameter @RateCenterName has no default value."

RateCenterID is the primary key

string updateSql = "UPDATE [RateCenters] " + "SET [RateCenterName] = @RateCenterName, [Province]= @Province, [QuantityThreshold] =@QuantityThreshold  " + "WHERE [RateCenterID]=@RateCenterID";

string ratecenterID;

    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
        DropDownList ddl = (DropDownList)row.FindControl("DropDownList2");
        TextBox rateCenterName = (TextBox)row.FindControl("TextBox1");
        TextBox quantityThreshold = (TextBox)row.FindControl("TextBox2");

        OleDbConnection conn = new OleDbConnection(ConfigurationManager.ConnectionStrings["DBConnection"].ToString());
        OleDbCommand cmd = null;

        try
        {
            conn.Open();
            cmd = new OleDbCommand(updateSql, conn);
            cmd.Parameters.Add("@RateCenterName", OleDbType.VarChar).Value = rateCenterName.Text;
            cmd.Parameters.Add("@Province", OleDbType.VarChar).Value = ddl.SelectedValue;
            cmd.Parameters.Add("@QuantityThreshold", OleDbType.VarChar).Value = quantityThreshold.Text;

            cmd.Connection = conn;
            cmd.ExecuteNonQuery();

            GridView1.EditIndex = -1;
            GridView1.DataBind();
        }
        catch (OleDbException ex)
        {
            throw (ex);
        }
        finally
        {
            cmd.Dispose();
            conn.Close();
            conn.Dispose();
        }
    }

Kindly help me to solve this issue.

Regards,

Arjun

解决方案

Your query takes four parameters (@RateCenterName, @Province, @QuantityThreshold and @RateCenterID), but you're only passing three.

@RateCenterID is missing.

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